# CVE-2026-11894: Realtek BEE Bluetooth HCI driver double-free in send callback

Source: https://junglewise.ai/threats/cve-2026-11894-realtek-bee-bluetooth-hci-driver-double-free-in-send-callback  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-11894 · Severity: medium · CVSS 5.9 · Published 2026-08-11

A flaw in Realtek's Bluetooth HCI driver violates buffer ownership rules, causing a transmitted buffer to be freed twice when errors occur—once by the driver and again by the host. This memory corruption can crash Bluetooth-enabled devices or enable further attacks. Remote Bluetooth peers can trigger the error conditions through heavy traffic.

Vendors: [Realtek](https://junglewise.ai/threats/vendors/realtek).

## Quick answers

**Is CVE-2026-11894 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-11894 being exploited in the wild.

**How severe is CVE-2026-11894?** Medium severity, with a CVSS score of 5.9, published 11 August 2026.

**Which products and versions are affected?** Realtek BEE Bluetooth HCI driver.

**Is there a fix for CVE-2026-11894?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-11894 attacked?** It is attacked over the network, in device firmware.

**Am I affected by CVE-2026-11894?** Check whether you run Realtek BEE Bluetooth HCI driver. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a double-free (CWE-415) and use-after-free read (CWE-416) in the bt_hci_bee_send() function in drivers/bluetooth/hci/hci_bee.c. The driver violates the bt_hci_driver_api contract by unconditionally calling net_buf_unref() on all error paths; the host caller then unrefs the same buffer again, corrupting the net_buf pool. Additionally, error-path code dereferences buf->len after the unref, reading freed memory. The vulnerability is reachable when the controller's host-to-controller buffer allocation fails or the controller send fails (resource-exhaustion or I/O conditions). A remote Bluetooth peer can indirectly trigger these conditions via heavy host transmit activity, leading to device crashes and potential memory corruption. The fix separates success and error paths, returning early from errors without unreffing and unreffing only on success.

## Affected products

- Realtek BEE Bluetooth HCI driver

## Timeline

- 2026-08-11: disclosed